Brown dye and process of making same



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- WILLIE-hi B.-RICHARDSON, OZ VIELMINGTON, NQRTH CAROLINA.-

nnown DYE Ann rnocnss or MAKING same.

No Drawing. Application filed May T 0 all whom it may concern:

Be it known that 1, WILLIAM B. Brennanson, a citizen of the United States, residing at l l ihnington, in the county or New Hanover and State of North Carolina, have inrented -ertain new and useful Improvements in Brown Dyes and Processes of Making Same; and i do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The present invention relates to the pro-- duction of dyes by the treatment of dihydroxy-naphthalene, and in this operation it is preferable to employ the l-o-di-hydroxynaphthalene, which may be produced in any suitable manner, and which may readily be obtained in a pure condition. The di-hydroXy-naphthalene is treated with concentrated nitric acid, the reaction mixture being preferably kept cold during the reaction and the mixture, after the addition oi nitric acid, preferably being allowed to stand in the cold itor several hours or over-night. If a highly concentrated nitric acid is employed, for example, one having a specific gravity of about 1.42, then it is necessary to keep the temperature low during the reaction. If a considerably weaker acid is employed, it is not necessary to keep the reaction mixture cold.

is a specific example of the process, the following is given:

5.5 parts, by weight, of 1-5-di-hydroxynaphthalene was slowly added with constant stirring to 54-.6 parts, by weight, of nitric acid of 1.3 specific gravity. The stirring was continued for an hour, then 7 parts, by weight, or 1.42 specific gravity nitric acid were added and the mixture well stirred.

he mixture was then allowed to stand for about thirty minutes. The reaction prod ucts were then poured into 100 parts or more of water, the solid reaction product was thereby preci ntated, separated from the dilute acid by filtration and washed with water a number or times. A reddish brown product was obtained, whereas the original dihydroxynaphthalene used was of a somewhat grayish color. During the treatment, it was not necessary to watch the temperature carefully, and the solution warmed up slightly during the operation.

The brownish pulverulent product is in- Specification of Letters Patent. Patentgd App, 11 1922.

8, 192a. Serial no. erases.

soluble or only very slightly soluble in water, and in dilute nitric and sulfurous acids, but is very soluble in alkali solutions such as ammonia and sodium carbonate. 7 It dissolves or decomposes and goes into solution in nitric acid of 1.42specific gravity, and is not re-precipitated by the addition of a large quantity of ammonia water. The product does not seem to be entirely uniform, several samples having been tested, giving a percentage of nitrogen bet-ween 3.75 and 5.5, and the latter percentage is somewhat lower than the theoretical per cent of nitrogen in mono-nitro-l-5-hydroxy-naphthalene. These analyses were made by standard fertilizer methods, and although they show absolutely that there is as much as 3.75 per cent, they do not absolutely prove that there is not more than 5.5 per cent nitrogen, since some of the nitrogen may have been lost during the analysis.

In a different example of the process, a

considerably stronger nitric acid was employed. During this operation it was necessary to cool the mixture during the reaction to prevent decomposition of the product. I am not prepared to give a structural formula of the product but I believe that the same is a nitro-derivative.

The reddish brown material forming the product dyes unmordanted silk a brilliant light brown, dyes unmordanted wool a somewhat darker shade of brown, and dyes tannin-mordanted cotton a grayish brown.

Iclaim:

1. A dyestu'lt constituting a reddish-brown solid material capable of dyeing unmordanted silk a brilliant light brown color, capable of dyeing unmordanted wool a slightly darker shade of brown, and capable of dye ing tanninmordanted cotton a grayish brown color, which dyestufl may be prepared by reacting upon a di-hydroXy-naphthalene with nitric acid.

2. A dyestutl constituting a reddish-brown solid material capable of dyeing unmordanted silk a brilliant light brown color, capable of dyeing unmordated wool a slightly darker shade of brown, and capable of dyeing tannin-mordanted cotton a grayish brown color, which dyestuii may be prepared by reacting upon 1-5-di-hydroxynaphthalene with nitric acid.

3. A dyestutf constituting a reddish-brown solid material capable of dyeing unmordante'd silk a brilliant light brown color, ingnot' substantially less than 5.5% of nicapable of dyeing unmordanted wool a trogen. slightly'darkeir shade of brown, andcap'ahle. 5. A-Process ofproducing a'dyes tuf'f which of dyeing tannin-inordanted cotton a graycomprises treating a di-hydroxy-naphthaish brown color, which dyestuif may be-p're- 'lene iiv'ith nitric 'ac'id, and thereafter 'prepared by reacting upon l-5-di-hydroxy= cipitating the dyes'tufi. I i naphthalenewith'nitric acid, such roduct 6. Apro'oess of producinga dyestuif Which 25 containing not less than-about 3. 5% of comprises treating 1-5-di-hydroxy-naphthanitrogen. lene"with nitric acid of about l';3speoific 10 4. Adyesti ffconstitutingareddish-brown gravity, at about ordinary room temperasolid "material capab'le'of dyeing uninorture, and thereafterprecipitating the dye capable "oi dyeing unmor'danted 'wool a In testimony whereofl affix my signature slightly darker shade of brown, andcapable in presence' of twofivitnesses.

""15 ofdyeingtanninfinordanted cotton 21 grayish 'WILLIAM B; RICHARDSON.

brown color, which dyestnfi' may be prepared Witnesses; by {reacting upon 1 5'-di-hydroXy-naphthafJo NJ. FURIJONG, lene with nitric'acid,such' product contain- H. ILFORIL dantedsilk' a'hriiliant'light'brown color, st 'iif, 30V 

